Hybrid inorganic / organic color effect materials and production thereof

ABSTRACT

A color effect material is composed of a plurality of encapsulated substrate platelets in which each platelet is encapsulated with a first layer which acts as a reflector to light directed thereon, a visibly transparent second organic layer encapsulating the first layer in which the second layer provides an optically variable reflection of light impinging thereon and a third layer encapsulating the second layer and being selectively transparent to light directed thereon.

BACKGROUND OF THE INVENTION

[0001] Optically variable pigments have been described in the patentliterature since the 1960s. Hanke in U.S. Pat. No. 3,438,796 describesthe pigment as being “thin, adherent, translucent, light transmittingfilms or layers of metallic aluminum, each separated by a thin,translucent film of silica, which are successively deposited undercontrolled conditions in controlled, selective thickness on centralaluminum film or substrate.” These materials are recognized as providingunique color travel and optical color effects.

[0002] The prior art approaches to optically variable pigments havegenerally adopted one of two techniques. In the first, a stack of layersis provided on a temporary substrate which is often a flexible web. Thelayers are generally made up of aluminum and MgF₂. The stack of film isseparated from the substrate and subdivided through powder processinginto appropriately dimensioned particles. The pigments are produced byphysical techniques such as physical vapor deposition onto thesubstrate, separation from the substrate and subsequent comminution. Inthe pigments obtained in this way, the central layer and all otherlayers in the stack are not completely enclosed by the other layers. Thelayered structure is visible at the faces formed by the process ofcomminution.

[0003] In the other approach, a platelet shaped opaque metallicsubstrate is coated or encapsulated with successive layers ofselectively absorbing metal oxides and non-selectively absorbing layersof carbon, metal and/or metal oxide. To obtain satisfactory materialsusing this approach, the layers are typically applied by chemical vapordeposition techniques in a fluidized bed. A major shortcoming of thistechnique is that fluidized bed processes are cumbersome and requiresubstantial technical infrastructure for production. An additionallimitation related to the substrates utilized is that traditional metalflakes usually have structural integrity problems, hydrogen outgassingproblems and other pyrophoric concerns.

[0004] The prior art approaches suffer from additional disadvantages.For instance, certain metals or metal flake such as chromium andaluminum, specifically when they are used as outer layers may haveperceived health and environmental impacts associated with their use.The minimization of their use in optical effect materials should beadvantageous due to their perceived impact.

SUMMARY OF THE INVENTION

[0005] The present invention provides a color effect material comprisinga platelet-shaped substrate encapsulated with(a) a first layer highlyreflective to light directed thereon; (b) a visibly transparent secondorganic layer encapsulating the first layer and providing a variablepathlength for light dependent on the angle of incidence of lightimpinging thereon in accordance with Snell's Law; and (c) a selectivelytransparent third layer to light directed thereon.

BRIEF DESCRIPTION OF THE DRAWING

[0006]FIG. 1 represents a modified plow type mixer under vacuum and atelevated temperature. The reactor consists of refractory tube 1containing a ceramic boat 2 filled with polymer precursordichlorodipara-xylylene. The precursor is volatilized in the tube andenters the pyrolysis furnace 3 operating at a temperature greater thanabout 600° C. Under elevated temperature, the precursor is convertedinto a highly reactive monomeric vapor. The reactive monomer istransported to the main chamber of the evacuated mixer while beingmaintained at about 0.1 torr by vacuum pump 10. The reactive monomerenters the mixing chamber through the tapered ceramic tube 5 where itimmediately comes in contact with particles 11 which are mechanicallyaerosolized by mixing blades 6. The mixing blades are driven by motor 8having a shaft 7 extending into the mixer 4 through vacuum seal 9.

DESCRIPTION OF THE INVENTION

[0007] It is an object of the present invention to provide novel hybridinorganic/organic color effect materials (HIO-CEMs) which can also beprepared in a reliable, reproducible and technically efficient manner.This object is achieved by a HIO-CEM comprising a platelet-shaped shapedsubstrate coated with: (a)a first layer highly reflective to lightdirected thereon; and (b) a visibly transparent second organic layerencapsulating the first layer in which the second layer consists of alow index of refraction material, typically a refractive index from 1.3to 2.5 and more specifically between 1.4 and 2.0, that provides avariable path length for light dependent on the angle of incidence oflight impinging thereon; and (c) a selectively transparent third layerto light directed thereon.

[0008] The degree of reflectivity for the first encapsulating layershould be from 100% to 5% reflectivity, whereas the selectivetransparency of the third encapsulating layer should be from 5% to 95%transmission. More specifically, one would prefer to have 50-100%reflectivity and 50-95% transparency for the first and thirdencapsulating layers, respectively. The degree of reflectivity andtransparency for different layers can be determined by a variety ofmethods such as ASTM method E1347-97, E1348-90 (1996) or F1252-89(1996).

[0009] The substrate can be mica, aluminum oxide, bismuth oxychloride,boron nitride, glass flake, iron oxide-coated mica (ICM), silicondioxide, titanium dioxide-coated mica (TCM), copper flake, zinc flake,alloy of copper flake, alloy of zinc flake, or any encapsulatable smoothplatelet.

[0010] The first and third layers can be the same or different such asprecious metals (i.e., silver, gold, platinum, palladium, rhodium,ruthenium, osmium and/or iridium or alloys thereof), copper, zinc, analloy of copper or an alloy of zinc, silicon, titanium dioxide, ironoxide, chromium oxide, a mixed metal oxide, and aluminum. Of course,when the substrate is copper flake, zinc flake, alloy of copper flake oralloy of zinc flake, there is no need for such a first layer since itwould be part of the substrate.

[0011] The second encapsulating layer can be any organic material suchas polymer, for example and preferably paraxylylene polymers andpolydivinylbenzene.

[0012] An advantage of the present invention is the wide variety ofvisibly transparent polymers that can be easily processed andeconomically employed. Of particular advantage is the use ofpara-xylylene polymers, the monomers of which can be produced inquantitative yields via thermal cleavage of cyclic dimmers without theproduction of gaseous by products. Additional advantages of thesepolymers would include their superior dimensional stability with respectto changes in relative humidity and unique optical, chemical andmechanical properties. The above advantages are imperative when beingutilized as an optical encapsulation for controlling light andapplications involving a variety of environments. Prior art has alwaysfocused on established, however limiting, inorganic materials. Thehistorical view of polymer technology is their poor thermal andmechanical stability and thus were ignored prior to the presentinvention.

[0013] Another advantage of the present invention is that one does nothave to start with a traditional particulate metal flake which may havestructural integrity problems, hydrogen outgassing problems and a hostof other perceived issues (pyrophoric and environmental concerns)typically associated with metal flakes. The precious metals when used inthis invention are much more chemically stable than traditionalparticulate metal flakes such as aluminum and generally prefer to be intheir non-oxidized metallic ground state. Furthermore, silver ispreferred when employed as one of the reflecting layers, as it canmaximize the chromaticity of the reflected color(s) of the HIO-CEM. Inaddition, when silver is used as the final (outer) layer of theparticle, it imparts electrical conductivity to the HIO-CEM which may bedesirable in some applications such as powder coatings. Advantages canalso be realized when utilizing alloys as the first and/or thirdencapsulating layer. For instance, brass alloy when used in thisinvention is much more chemically stable than aluminum and is known tohave long term weather stability. Brass is nearly chemically inert whichallows great flexibility in the chemical systems employed in themanufacture of such effect materials and in their applications in enduses such as in paint, ink and polymer systems. Another advantage overthe prior art is that brass when used as one of the reflecting layers inthis invention, is a good reflector of white light and at the same timeprovides an attractive bulk color. The same would be true for analuminum-copper alloy. Such an alloy is advantageous due to itsattractive bulk color effect, while maintaining high reflectivity.Additionally, both brass and copper coated substrates provide thedecorative/functional attributes of brass and copper, however under moreenvironmentally favorable terms due to the reduced metal concentrationsince the HIO-CEMs of the present invention are not pure brass orcopper, rather brass or copper coated inorganic substrates. In addition,one can produce the HIO-CEMs where the outer encapsulating layers arenot made of brass, or other alloys.

[0014] A surprising aspect of the present invention is that costeffective composite materials are created with desirable optical effectand conductive properties.

[0015] Organic polymer layers can be deposited by aqueouspolymerization/precipitation, solvent polymerization/deposition orchemical vapor deposition. For aqueous deposition, the polymer isdeposited from aqueous monomers and initiators. For solvent deposition,the polymer is solubilized in an appropriate solvent and deposited onthe substrate during solvent evaporation, or alternatively monomersadded to the solvent would be initiated and polymerized on the surfaceof the coated substrate. For chemical vapor deposition, the polymer isdeposited from gaseous monomers such as hexamethylene diisocyanate,toluene diisocyanate or isophorone diisocyanate and polymerized on thecoated substrate surface with hexamethylene diamine or hydrazine. Inaddition, parylene can be directly deposited in the gas phase from thethermal cleavage of cyclic dimmers.

[0016] Inorganic metal layers are preferably deposited by electrolessdeposition and the non-metal layers preferably by sol-gel deposition. Anadvantage of electroless deposition (Egypt. J. Anal. Chem., Vol. 3,118-123 (1994)) is that it is a world wide established chemicaltechnique, not requiring cumbersome and expensive infrastructurecompared to other techniques. The electroless deposition technique alsoallows one to control the degree of reflectivity of light quiteaccurately and easily by varying the metal film thickness. Additionally,the known procedures are generalized procedures capable of beingutilized for coating a variety of surfaces. Furthermore, anencapsulating layer of a metal or metal oxide can also be deposited ontoany of the substrates by chemical vapor deposition from an appropriateprecursor (The Chemistry of Metal CVD, edited by Toivo T. Kodas and MarkJ. Hampden-Smith; VCH Verlagsgesellschaft GmbH, D-69451 Weinheim, 1994,ISBN 3-527-29071-0).

[0017] For deposition of alloys, a unique method has been developed asdescribed in U.S. Pat. No. 4,940,523 which outlines a “process andapparatus for coating fine particles.” In addition, the technique can beused to deposit pure metals such as chromium, platinum, gold andaluminum, or ceramics.

[0018] The products of the present invention are useful in automotive,cosmetic, industrial or any other application where metal flake,iridescent materials, pearlescent or absorption pigments aretraditionally used.

[0019] The size of the platelet-shaped substrate is not critical per seand can be adapted to the particular use. In general, the particles haveaverage largest major dimensions of about 5-250 μm, in particular 5-100μm. Their specific free surface area (BET) is in general from 0.2 to 25m²/g. Of course similar size substrates can be made in which theirsurface area has been engineered to a much higher or lower value.

[0020] The HIO-CEMs of the invention are notable for multipleencapsulation of the platelet-shaped substrate.

[0021] The first metallic encapsulating layer is highly reflective tolight directed thereon. The thickness of the first layer is not criticalso long as it is sufficient to make the layer highly reflective. Ifdesirable, the thickness of the first layer can be varied to allow forselective transmission of light. The thickness of the first metalliclayer may be 5 nm to 500 nm and preferably 25 nm to 100 nm for copper,zinc, silver, aluminum or alloys thereof. A metallic layer thickness outof the above-mentioned ranges will typically be either completely opaqueor allow for substantial transmission of light. In addition to itsreflective properties, the metallic encapsulating layer may exhibitunique bulk color effects depending on the film thickness. For example,a brass coating thickness of >50 nm will begin to exhibit a metallicgold bulk color, while maintaining good reflectivity. The mass percentof the coating will be directly related to the surface area of theparticulate substrate being utilized.

[0022] The second organic encapsulating layer must provide a variablepathlength for light dependent on the angle of incidence of lightimpinging thereon and therefore, any low index of refraction materialthat is visibly transparent may be utilized. Preferably, the secondlayer is selected from the group consisting of parylene,polytetrafluoroethylene, polyvinylacetate, polydivinylbenzene,ethylcellulose, polymethylmethacrylate, polyvinylalcohol, polyurethanesand polyureas. More preferably, the second layer is a parylene orpolydivinylbenzene.

[0023] The thickness of the second layer varies depending on the degreeof color travel desired. In addition, the second layer will have avariable thickness depending on a variety of factors, especiallyrefractive index. Materials having a refractive index around 1.5 tend torequire a film thickness of a few hundred nanometers for generation ofunique color travel. For instance, a second layer has a preferablethickness of about 75 to 500 nm for parylene, polytetrafluoroethylene,polyvinylacetate, polydivinylbenzene, ethylcellulose,polymethylmethacrylate, polyvinylalcohol, polyurethanes and polyureas.

[0024] In one embodiment, the second layer is encapsulated by aselectively-transparent third layer that allows for partial reflectionof light directed thereon. Preferably, the third encapsulating layer isselected from the group consisting of copper, silicon, titanium dioxide,iron oxide, chromium oxide, a mixed metal oxide, aluminum or alloysthereof. More preferably, the third encapsulating layer is one or moreof the precious metals selected from the group consisting of silver,gold, platinum, palladium, rhodium, ruthenium, osmium and/or iridium oralloys thereof.

[0025] Of course, the third layer can also contribute to theinterference color of the pigment. Its thickness can vary but mustalways allow for partial transparency. For instance, a third layer has apreferable thickness of about 5 to 45 nm for silicon; about 2 to 25 nmfor aluminum; about 2 to 25 nm for copper; about 2 to 20 nm for zinc;about 1 to 25 nm for titanium nitride; about 10 to 60 nm for iron oxide;about 10 to 60 nm for chromium oxide; about 10 to 120 nm for titaniumdioxide; about 5 to 100 nm for a mixed metal oxide, about 5 to 50 nm forsilver; about 3 to 30 nm for gold; about 3 to 30 nm for platinum; andabout 5 to 30 nm for palladium. The precious metal and base metal alloysgenerally have a similar film thickness requirement compared to the puremetal. It is recognized that a film thickness out of the above range maybe applicable depending on the desired effect.

[0026] All the encapsulating layers of the CEM of the invention arealtogether notable for a uniform, homogeneous, film-like structure thatresults from the manner of preparation according to the invention.

[0027] In the novel process for preparing the coated platelet-likesubstrates, the individual coating steps are each effected by sputterdeposition, electroless deposition, complex coacervation, vapordeposition or hydrolysis/condensation of suitable starting compounds inthe presence of the substrate particles to be coated. Alloys, such asbrass, can be deposited by a sputtering technique as described in U.S.Pat. No. 4,940,523. In addition, pure metals such as aluminum, copperand zinc, as well as others, can be sputter deposited. Electrolessdeposition of metals is an established technique for coating particulatematerials. For instance, metals can be deposited by electrolesstechniques from reduction of aqueous salts of the metals, such asHAuCl₄, AgNO₃, CuSO₄, H₂PtCl₆, PdCl₂. Polymers such as parylene canreadily be deposited in the vapor phase according to well establishedtechniques. Detailed parylene chemistry, along with vapor depositiontechniques, is taught to us in U.S. Pat. 3,342,754 by Gorham, thisdisclosure of which is hereby incorporated by reference. It isunderstood that one can control and vary the refractive index by themultitude of polymer structures prepared by the teachings of Gorham, aswell as other polymer synthesis techniques. Titanium dioxide can bedeposited from tetraalkoxides such as titanium tetraethoxide, halidecompounds such as titanium tetrachloride and sulfate compounds such astitanium sulfate, titanium nitride from titanium tetrachloride,tetrakis(diethylamido)titanium (TDEAT) andtetrakis(dimethylamido)titanium (TDMAT); iron oxide from iron carbonyl,iron sulfate and iron chloride; and chromium oxide from chromiumcarbonyl and chromium chloride.

[0028] In general, the synthesis of a hybrid inorganic/organic coloreffect material can be as follows: a platelet material such as mica issuspended while stirring in an aqueous medium. To the suspension isadded a metal precursor capable of depositing metal on the substrate byelectroless deposition, along with a suitable reducing agent. The highlyreflective metal coated substrate is filtered, washed and dried. Anaqueous deposition process can be employed for the deposition of anorganic polymer on the metal coated mica or other substrate. The polymeris deposited from aqueous monomers and initiators. The organic materialencapsulated metal coated platelet is filtered, washed and re-suspendedin a stirred aqueous medium. To the aqueous medium is added a metalprecursor capable of depositing metal on the substrate by electrolessdeposition, along with a suitable reducing agent. The metal solution forelectroless deposition is added as described above allowing for thedeposition of a selectively transparent metal coating. The finalparticulate product is washed, dried and exhibits optical color effectsas a function of viewing angle.

[0029] Depending on the thickness of the low refractive index secondencapsulating layer, the final HIO-CEM will display multiple differentcolor effects as a function of viewing angle (red, orange, green,violet). The platelet substrate acts as a carrier substrate. It may, ormay not, have a contribution or effect on the final optical propertiesof the particulate.

[0030] The hybrid inorganic/organic color effect materials (HIO-CEMs) ofthe invention are advantageous for many purposes, such as the coloringof paints, printing inks, plastics, glasses, ceramic products anddecorative cosmetic preparations. Their special functional propertiesmake them suitable for many other purposes. The CEMs, for example, couldbe used in electrically conductive or electromagnetically screeningplastics, paints or coatings or in conductive polymers. The conductivefunctionality of the CEMs makes them of great utility for powder coatingapplications.

[0031] The above-mentioned compositions in which the compositions ofthis invention are useful are well known to those of ordinary skill inthe art. Examples include printing inks, nail enamels, lacquers,thermoplastic and thermosetting materials, natural resins and syntheticresins. Some non-limiting examples would include polystyrene and itsmixed polymers, polyolefins, in particular polyethylene andpolypropylene, polyacrylic compounds, polyvinyl compounds, for examplepolyvinyl chloride and polyvinyl acetate, polyesters and rubber, andalso filaments made of viscose and cellulose ethers, cellulose esters,polyamides, polyurethanes, polyesters, for example polyglycolterephthalates, and polyacrylonitrile.

[0032] For a well-rounded introduction to a variety of pigmentapplications, see Temple C. Patton, editor, The Pigment Handbook, volumeII, Applications and Markets, John Wiley and Sons, New York (1973). Inaddition, see for example, with regard to ink: R. H. Leach, editor, ThePrinting Ink Manual, Fourth Edition, Van Nostrand Reinhold(International) Co. Ltd., London (1988), particularly pages 282-591;with regard to paints: C. H. Hare, Protective Coatings, TechnologyPublishing Co., Pittsburgh (1994), particularly pages 63-288. Theforegoing references are hereby incorporated by reference herein fortheir teachings of ink, cosmetic, paint and plastic compositions,formulations and vehicles in which the compositions of this inventionmay be used including amounts of colorants. For example, the pigment maybe used at a level of 10 to 15% in an offset lithographic ink, with theremainder being a vehicle containing gelled and ungelled hydrocarbonresins, alkyd resins, wax compounds and aliphatic solvent. The pigmentmay also be used, for example, at a level of 1 to 10% in an automotivepaint formulation along with other pigments which may include titaniumdioxide, acrylic lattices, coalescing agents, water or solvents. Thepigment may also be used, for example, at a level of 20 to 30% in aplastic color concentrate in polyethylene.

[0033] In the cosmetic field, these pigments can be used in the eye areaand in all external and rinse-off applications. They are restricted onlyfor the lip area. Thus, they can be used in hair sprays, face powder,leg-makeup, insect repellent lotion, mascara cake/cream, nail enamel,nail enamel remover, perfume lotion, and shampoos of all types (gel orliquid). In addition, they can be used in shaving cream (concentrate foraerosol, brushless, lathering), skin glosser stick, skin makeup, hairgroom, eye shadow (liquid, pomade, powder, stick, pressed or cream), eyeliner, cologne stick, cologne, cologne emollient, bubble bath, bodylotion (moisturizing, cleansing, analgesic, astringent), after shavelotion, after bath milk and sunscreen lotion.

EXAMPLE 1 Procedure For Evaluation of CEMs According to the Invention

[0034] The luster and color are evaluated using drawdowns on a hidingchart (Form 2-6 Opacity Charts of the Leneta Company) both visually andinstrumentally. A drawdown on the black portion of the card displays thereflection color while the white portion displays the transmission colorat non-specular angles.

[0035] The drawdowns are prepared by incorporating 3-12% HIO-CEM in anitrocellulose lacquer, with the concentration dependent on the particlesize distribution of the HIO-CEM. For example, a 3% drawdown wouldlikely be used for an average HIO-CEM particle size of 20 μm while a 12%drawdown might be used for an average HIO-CEM particle size of 100 μm.The HIO-CEM-nitrocellulose suspension is applied to the drawdown cardusing a Bird film application bar with a wet film thickness of 3 mil.

[0036] When these drawdowns are observed visually, a variety of colorscan be observed dependent on the viewing angle, such as, aqua to blue toviolet. The degree of color travel observed is controlled by thethickness of the low index of refraction layer. Other quantifiableparameters commonly used to describe effect pigments, such as lightness(L*) and chromaticity (C*), can be controlled through both: a) thechoice of materials used as lower reflecting and top, selectivelytransmitting encapsulating layers and b) the thickness of said lower andtop encapsulating layers.

[0037] The drawdown is further characterized using agoniospectrophotometer (CMS-1500 from Hunter). The reflectivity vs.wavelength curve is obtained at various viewing angles. The color travelfor the HIO-CEM is described using the CIELab L*a*b* system. The data isrecorded both numerically and graphically. The numerical recording for aHIO-CEM representative of that obtained in Example 2 is as follows:Approximate Approximate Approximate Silver Polymer Silver Thickness1^(st) Thickness Thickness Encapsu- 2^(nd) Encapsu- 3^(rd) Encapsu-Incident lating lating lating Angle Layer (nm) Layer (nm) Layer (nm) L*A* B* 0 50 250 4 70 48 −30 10 50 250 4 71 48 −28 20 50 250 4 73 45 −2230 50 250 4 76 37 −10 40 50 250 4 80 24 7 50 50 250 4 84 10 27 60 50 2504 88 1 36 70 50 250 4 90 0 27 0 50 75 4 73 4 37 0 50 100 4 53 50 −51 050 125 4 78 −47 −21 0 50 150 4 96 −9 14 0 50 175 4 95 2 24 0 50 200 4 910 41 0 50 225 4 84 11 30 0 50 250 4 70 48 −30 0 50 275 4 68 26 −36 0 50300 4 79 −46 −11 0 50 325 4 90 −43 23 0 50 350 4 93 −10 44 0 50 400 4 8334 −2

[0038] The L*a*b* data characterizes the appearance of the sample. L* isthe lightness/darkness component, a* describes the red/green colorcomponent, b* represents the blue/yellow component.

EXAMPLE 2 Preparation of Ag/polydivinylbenzene/Ag CEM

[0039] Fifty grams of silver coated borosilicate flake is placed in a 1liter oven dried morton flask containing 650 ml of mineral spirits(boiling point 179-210° C.) previously dried over anhydrous magnesiumsulfate. A condenser containing drierite desiccant is fitted to one neckof the 3-neck morton flask with a stirring shaft and temperature probefitted to the other two necks. The suspension is stirred at 250 rpm'sand heated to 100° C. To the heated suspension is added 0.82 grams ofbenzoyl peroxide crystals followed by 7.4 grams (0.057 moles) ofdivinylbenzene (technical purity, 80% mixture of isomers). The reactionis allowed to stir at 100° C. for 18 hours and then cooled to 45° C. Theentire suspension is then filtered on an 11 cm Buchner funnel using #2Whatman filter paper, rinsed with ethanol and the product dried at 120°C. The calculated yield of the PDVB is 82% and calculated film thicknessis 300 nanometers. The resulting PDVB coating is visibly transparent anddoes not decrease the high reflectivity of the silver coatedborosilicate flake.

[0040] Ten grams of the above PDVB encapsulated silver coated flake isdispersed in 100 ml of distilled water in a 250 ml 3-neck flask. Astirring shaft, pH meter and temperature probe are fitted to the 3-neckflask. The suspension is stirred at 250 rpms. To the suspension is addeda colloidal solution of 0.10 grams of tin chloride in 100 ml ofdistilled water. After 10 minutes of stirring, the suspension isfiltered on an 11 cm Buchner funnel using #2 Whatman filter paper andrinsed with distilled water. The rinsed presscake is then transferred toa 250 ml 3-neck morton flask fitted with a stirring shaft, pH meter andtemperature probe. A solution of 1.0 grams of dextrose in 75 ml ofdistilled water is added to the flask and stirred at 250 rpm's. Throughthe temperature probe port of the flask a solution of 1.0 grams silvernitrate in 100 ml of distilled water containing a molar excess of2-amino-2-methyl propanol is added at 10 ml per minute.

[0041] After a few minutes, the slurry displays a brilliant greenish togold color flop. The entire suspension is then filtered on an 11 cmBuchner funnel using #2 Whatman filter paper, rinsed with distilledwater and the product dried at 120° C. In bulk powder form the productexhibits pronounced color effects based on viewing angle varying fromgreen to gold to red interference effects.

EXAMPLE 3

[0042] Silver coated borosilicate particles are introduced into amodified plow type mixer as described in FIG. 1. The reactor consists ofrefractory tube 1 containing a ceramic boat 2 filled with polymerprecursor dichloro-di-p-xylylene. The precursor is volatilized in thetube and enters the pyrolysis furnace 3 operating at a temperature ofabout 600° C. Under elevated temperature, the precursor is convertedinto a highly reactive monomeric vapor. Encapsulation and polymerizationof the particulate material involves the pyrolysis cleavage of themethylene-methylene bonds in dichloro-di-p-xylylene resulting in twomolecules of reactive monomer chloro-p-xylylene. The reactive monomer istransported to the main chamber of the evacuated mixer while beingmaintained at about 0.1 torr by vacuum pump 10. As the reactive monomerenters the aerosolized cloud of particles 11 through the tapered ceramictube 5, it is adsorbed on the particle surfaces followed byinstantaneous polymerization. Mechanical aerosolization of the powdersis achieved by mixing blades 6 driven by motor 8 having a shaft 7extending into the mixer 4 through vacuum seal 9. The resultingmicroencapsulated particles have a uniform optical quality coating ofparylene. The powder is eventually removed from the reactor and thefinal silver coating is applied as in Example 2.

EXAMPLE 4

[0043] A HIO-CEM prepared according to example 2 is incorporated intopolypropylene step chips at 1% concentration. The step chips areappropriately named since they have graduating thickness at each stepacross the face of the chip. The graduating steps allow one to examinethe different effect of the HIO-CEM based on polymer thickness.

EXAMPLE 5

[0044] A HIO-CEM prepared according to example 2 is incorporated into anail enamel. 10 g of the HIO-CEM is mixed with 82 g of suspendinglacquer SLF-2, 4 g lacquer 127P and 4 g ethyl acetate. The suspendinglacquer SLF-2 is a generic nail enamel consisting of butyl acetate,toluene, nitrocellulose, tosylamide/formaldehyde resin, isopropylalcohol, dibutyl phthalate, ethyl acetate, camphor, n-butyl alcohol andsilica.

EXAMPLE 6

[0045] A 10% by weight HIO-CEM from example 2 is sprayed in a polyesterTGIC powder coating from Tiger Drylac using a PGI corona Gun #110347.The HIO-CEM is mixed in a clear polyester system and sprayed over a RAL9005 black pigmented polyester powder. The HIO-CEM is highly attractedto the ground metal panel due to its electrical properties.Additionally, due to its high affinity to orient closely to the surfaceit produces a finish that is high in distinctness of image (DOI). Itdoes not require an additional clear coat to reduce protrusion oftencaused by traditional pearlescent and metal flake pigments.

EXAMPLE 7

[0046] A 10% dispersion of the HIO-CEM prepared according to example 2is mixed into a clear acrylic urethane basecoat clearcoat paint systemDBX-689 (PPG) along with various PPG tints to achieve desired color. Thetint pastes consist of organic or inorganic colorants dispersed atvarious concentrations in a solventborne system suitable with the DMDDeltron Automotive Refinish paint line from PPG. The completeformulation is sprayed using a conventional siphon feed spraygun onto4×12″ curved automotive type panels supplied by Graphic Metals. Thepanel is clear coated with PPG 2001 high solids polyurethane clear coatand air dried.

[0047] Various changes and modifications can be made in the process andproducts of the invention without departing from the spirit and scopethereof. The various embodiments disclosed herein were for the purposeof illustration only and were not intended to limit the invention.

What is claimed is:
 1. A hybrid inorganic/organic color effect materialcomprising a platelet-shaped substrate encapsulated with: (a) a firstlayer highly reflective to light directed thereon; and (b) a visiblytransparent second organic layer encapsulating the first layer andproviding a variable pathlength for light dependent on the angle ofincidence of light impinging thereon; and (c) a selectively transparentthird layer to light directed thereon.
 2. The hybrid inorganic/organiccolor effect material of claim 1, wherein the substrate is selected fromthe group consisting of mica, aluminum oxide, bismuth oxychloride, boronnitride, glass flake, iron oxide-coated mica, iron oxide coated glass,silicon dioxide, titanium dioxide coated mica, titanium dioxide coatedglass, copper flakes, zinc flakes, alloy of copper flakes, and alloy ofzinc flakes.
 3. The hybrid inorganic/organic color effect material ofclaim 1, wherein the first layer is selected from the group consistingof aluminum, copper, gold, palladium, platinum, silver, zinc, an alloyof aluminum, an alloy of copper, and an alloy of zinc.
 4. The hybridinorganic/organic color effect material of claim 1, wherein the firstlayer is an alloy of copper and zinc.
 5. The hybrid inorganic/organiccolor effect material of claim 1, wherein the first layer is an alloy ofaluminum and copper.
 6. The hybrid inorganic/organic color effectmaterial of claim 1, wherein the first layer is an alloy of aluminum andzinc.
 7. The hybrid inorganic/organic color effect material of claim 1,wherein the first layer is copper.
 8. The hybrid inorganic/organic coloreffect material of claim 1, wherein the first layer is zinc.
 9. Thehybrid inorganic/organic color effect material of claim 1, wherein thefirst layer is selected from the group consisting of silver, gold,platinum, palladium, rhodium, ruthenium, osmium, iridium and alloysthereof.
 10. The hybrid inorganic/organic color effect material of claim9, wherein the first layer is silver.
 11. The hybrid inorganic/organiccolor effect material of claim 9, wherein the first layer is gold. 12.The hybrid inorganic/organic color effect material of claim 9, whereinthe first layer is platinum.
 13. The hybrid inorganic/organic coloreffect material of claim 9, wherein the first layer is palladium. 14.The hybrid inorganic/organic color effect material of claim 9, whereinthe first layer is copper.
 15. The hybrid inorganic/organic color effectmaterial of claim 9, wherein the first layer is said alloy.
 16. Thehybrid inorganic/organic color effect material of claim 1, wherein thesecond encapsulating layer is an organic polymer.
 17. The hybridinorganic/organic color effect material of claim 16, wherein the secondencapsulating layer is selected from the group consisting of parylene,polytetrafluoroethylene, polyvinylacetate, polydivinylbenzene,ethylcellulose, polymethylmethacrylate, polyvinylalcohol, polyurethanesand polyureas.
 18. The hybrid inorganic/organic color effect material ofclaim 16, wherein the second encapsulating layer is polydivinylbenzene.19. The hybrid inorganic/organic color effect material of claim 16,wherein the second encapsulating layer is parylene.
 20. The hybridinorganic/organic color effect material of claim 1, wherein the thirdencapsulating layer is selected from the group consisting of silver,gold, platinum, palladium, rhodium, ruthenium, osmium, iridium andalloys thereof.
 21. The hybrid inorganic/organic color effect materialof claim 20, wherein the third encapsulating layer is silver.
 22. Thehybrid inorganic/organic color effect material of claim 20, wherein thethird encapsulating layer is gold.
 23. The hybrid inorganic/organiccolor effect material of claim 20, wherein the third encapsulating layeris platinum.
 24. The hybrid inorganic/organic color effect material ofclaim 20, wherein the third encapsulating layer is palladium.
 25. Thehybrid inorganic/organic color effect material of claim 20, wherein thethird encapsulating layer is said alloy.
 26. The hybridinorganic/organic color effect material of claim 1, wherein the thirdlayer is selected from the group consisting of aluminum, copper,silicon, titanium dioxide, iron oxide, chromium oxide, a mixed metaloxide, aluminum, and alloys thereof.
 27. The hybrid inorganic/organiccolor effect material of claim 1, wherein the first layer is a sputterdeposited layer.
 28. The hybrid inorganic/organic color effect materialof claim 1, wherein the first layer is an electroless deposition layer.29. The hybrid inorganic/organic color effect material of claim 1,wherein the second layer is an aqueous polymerization precipitationlayer.
 30. The hybrid inorganic/organic color effect material of claim1, wherein the second layer is a solvent polymerization depositionlayer.
 31. The hybrid inorganic/organic color effect material of claim1, wherein the second layer is a chemical vapor deposition layer. 32.The hybrid inorganic/organic color effect material of claim 1, whereinthe substrate is platelet-shaped glass flake, the highly reflectivefirst encapsulating layer is silver, the second encapsulating layer ispolydivinylbenzene and the third encapsulating layer is a selectivelytransparent layer of silver.
 33. The hybrid inorganic/organic coloreffect material of claim 1, wherein the substrate is platelet-shapedglass flake, the highly reflective first encapsulating layer is silver,the second encapsulating layer is parylene and the third encapsulatinglayer is a selectively transparent layer of silver.
 34. A method ofmaking a hybrid inorganic/organic color effect material comprising: (a)coating a platelet-shaped substrate with a first layer highly reflectiveto light directed thereon; and (b) encapsulating the first layer with avisibly transparent second organic layer providing a variable pathlengthfor light dependent on the angle of incidence of light impingingthereon; (c) encapsulating the second layer with a selective transparentthird layer to light directed thereon.
 35. The method of claim 34,wherein the substrate is selected from the group consisting of mica,aluminum oxide, bismuth oxychloride, boron nitride, glass flake, ironoxide-coated mica, iron oxide coated glass, silicon dioxide, titaniumdioxide coated mica, titanium dioxide coated glass, copper flakes, zincflakes, alloy of copper flakes, and alloy of zinc flakes.
 36. The methodof claim 34, wherein the second layer is an organic polymer.
 37. Themethod of claim 34, wherein the second encapsulating layer is selectedfrom the group consisting of parylene, polytetrafluoroethylene,polyvinylacetate, polydivinylbenzene), ethylcellulose,polymethylmethacrylate, polyvinylalcohol, polyurethanes and polyureas.38. The method of claim 37, wherein the second layer ispolydivinylbenzene.
 39. The method of claim 37, wherein the second layeris parylene.